This invention relates to a chip conveyor, which conveys cutting chips produced in the operation of a machine tool, such as a lathe or the like, from a receiving position to a discharge position, and a chip-separating/recovery apparatus used with the chip conveyor.
As a conventional chip conveyor, the chip conveyor disclosed in Japanese Unexamined Utility Model Publication No. Sho 59-55645 has been proposed. This chip conveyor includes a circulating conveying member and a bucket removably located at the discharge position of the chips. Chips containing cutting oil are conveyed by the conveying member to the discharge position, and just after the chips reach the discharge position, they are received by the bucket. A number of small holes for filtering the cutting oil are provided in the bottom portion of the bucket.
Further, air is sprayed from the outlet of nozzle on the lower surface of the conveying member so that chips that have adhered to the lower surface of the conveying member fall into the bucket. The cutting oil adhered to the chips is recovered through an oil recovery pipe from the number of small holes of the bucket.
However, in the above-mentioned chip conveyor, since the air sprayed through the nozzle has insufficient peel force, the chips adhered to the lower surface of the conveying member by oil cannot be reliably separated or recovered. Although the chips can be separated from the conveying member by increasing the air pressure through the nozzle, not only is a special structure for preventing the flying of chips is needed, but also a supply source for a high-pressure fluid is needed.
On the other hand, the present applicant proposed a chip conveyor disclosed in Japanese Unexamined Patent Publication No. Sho 63-123656. In this chip conveyor, an endless type mesh belt is provided inside a horizontal frame and an inclined frame. The horizontal frame is arranged in a chip-receiving region, and chips from a machine tool are introduced onto the horizontal frame. Then, the conveyor belt is circulated within and along the horizontal frame and the inclined frame and the chips introduced onto the horizontal frame are conveyed to the upper end of the inclined frame, and the chips are discharged from the chip conveyor.
Further, a spraying member is arranged between the upper and lower traveling portions of the mesh belt in the horizontal frame. By spraying coolant toward the lower traveling portion of the mesh belt, the lower traveling portion of the mesh belt is cleaned. A recovery tank for recovering the coolant adhered to the belt and fine chips is arranged on the inclined frame.
However, in this chip conveyor also, the chips cannot be reliably removed by only spraying the coolant on the mesh belt. Further, not only is a special structure for preventing the flying of coolant and chips needed, but also a supply source for a high-pressure fluid is needed.
Even when the conveying member of the belt and the like passes through the chip-discharge position, if a piece of a chip is adhered to the conveying member, the chip can enter between sliding parts forming the conveying member to wear the parts. Further, the chip can enter between sliding parts of a mechanism that drives the conveying member, which will decrease the life of the driving mechanism. Moreover, when the remaining chips fall and accumulate in the receiving position, the accumulated chips must be manually removed, which is troublesome.
Further, Japanese Unexamined Utility Model Publication No. Sho 61-191849 describes a cutting-water separation apparatus used for a machine tool. This separation apparatus includes a tank for receiving chips from the machine tool, a chip conveyor for discharging the chips from the tank, a supporting plate, which receives cutting water dropping from the vicinity of a head pulley of the chip conveyor, and a pipe for recovering the cutting water dropped on the supporting plate.
When the endless conveying member of the chip conveyor is moved along a forward route from the tank to the head pulley, it conveys chips from the tank to the head pulley and drops the chips from the head pulley. Further, when the endless conveying member is moved along a return route from the head pulley to the tank, cutting water, which drops from the head pulley, is returned back to the tank through the supporting plate, the pipe, and the hose.
However, in this separation apparatus, it is hardly possible to recover chips that adhere to the conveying member. The supporting plate and pipe are used for recovery of only a small amount of cutting water, and the cutting water dropped on the supporting plate is collected into the pipe along the inclination of the supporting plate. The cutting water is not used for the separation of remaining chips adhered to the conveying member.
All of the chips put on the chip conveyor from the tank in the receiving position are not dropped into a recovery box from the chip conveyor in the discharge position, and some of the chips adhere to the conveyor by liquid crosslinking adhesion and are returned to the receiving position. The returned chips accumulate in the tank in the receiving position. In a case of aluminum machining, the rate of returned chips is more than 50%, which is a large amount, and the tank is immediately filled with the chips. In this case, after the operation of the machine tool is stopped and the cutting water is drained from the machine tool, the chips must be removed from the tank, which is troublesome.
In addition, since the chips accumulated in the tank are discharged, it is possible to use a screw conveyor. However, since the tank is usually provided on the ground, it is necessary to form an underground pit by an excavating operation to install the screw conveyor, which greatly increases the operating cost.
To prevent the provision of an underground pit, the tank may be located at a position higher than the ground. However, in this case, the machine tool itself, other than the tank, must also be located at a position higher than the ground, which also increases costs greatly. Further, the working position of workpieces becomes higher than necessary and the operation becomes inconvenient.
This invention has been made to solve the abovementioned problems. The object of the present invention is to provide a chip conveyor that can separate and recover chips remaining on a conveying member in the forward route so that the durability of the conveying member and the driving mechanism is improved, which improves the degree of freedom in locating the remaining chip separation apparatus to simplify the provision of the separation apparatus.
Further, in addition to the above object, another object of the present invention is to provide a chip separation/recovery apparatus the construction of which is simplified so that attachment and detachment operations with respect to a discharge portion of the chip conveyor is simplified.
To attain the above-mentioned object, in a preferred embodiment of the present invention, a chip conveyor is provided, in which chips discharged from a machine tool are received in a receiving region, the chips are conveyed to a discharge position spaced by a predetermined distance from the receiving region, and an endless conveying member is located for discharging the chips at the discharge position such that the conveying member can be circulated in a predetermined direction. In this chip conveyor a path from the receiving region to the discharge position is defined as a forward route of the conveying member. A path from the discharge position where returned to the receiving region is defined as a return route of the conveying member. A separation apparatus for separating chips from the conveying member is provided in the return route, and the separation apparatus causes a liquid to act on chips adhered to the conveying member after passing through the discharge position to reduce or remove the adhesion.
In another embodiment of the present invention, a chip separation/recovery apparatus used in the chip conveyor is provided. The apparatus includes a liquid storage tank containing a liquid, through which a conveying member passes on the return route of the conveying member, and a mechanism, which is provided in the liquid storage tank and which causes the conveying member to detour.